| 摘要 |
<p>Lubricants for pneumatic tyres for use when the tyre is operated in a deflated condition comprises (a) 100 pts. wt. of a mixt. of 4 parts ethylee glycol and >=1 part H2O; (b) 0.05-2 pts. wt. of a polyethylene oxide with a mol. wt. of ca. 500.000; (c) 0.15-2 pts. wt. of a polysaccharide with a mol. wt. of >=10.000; and (d) =8 pts. wt. of cellulose fibres with a length of 400 mu. The viscosity of the lubricant must be such that the fibres remain dispersed when the tyre is subjected to a centrifugal force of 200-g at 70 degrees C. Suitable polysaccharides include starch, cellulose and hemicellulose derivs. and natural gums and mucilages. The lubricant pref. has a viscosity of 100.000-400.000 cP at 25 degrees C, which should increase by >=10% at 85 degrees C. When applied to the inside wall of the tyre, the lubricant reduces the friction and heat generated by the rubbing of the upper and lower halves of the sidewall, so that the tyre can run flat for some time after a puncture. The lubricants are comparable with rubber, have good thermal and shear stability, and are capable of reducing leakage through punctures.</p> |
